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Leonard P. Rybak, MD, PhD

Research Professor
Department of Otolaryngology Head and Neck Surgery


Dr. Leonard P. Rybak is a research professor and ear, nose and throat specialist whose general otolaryngology practice focuses on sinus disease and obstructive sleep apnea. Dr. Rybak received his medical degree from the Medical College of Wisconsin-Milwaukee and completed his internship at Hennepin County Medical Center in Minneapolis. He completed a residency in otolaryngology and also obtained a PhD at the University of Minnesota-Minneapolis.

Dr. Rybak served as an assistant professor of otolaryngology at the University of Minnesota prior to coming to the SIU School of Medicine. Dr. Rybak's professional affiliations include the American College of Surgeons, and the American Academy of Otolaryngology - Head and Neck Surgery. Locally, he is a member of the Sangamon County Medical Society and of various committees at St. John’s Hospital and the SIU School of Medicine. He serves as president of the Sangamon County Chapter of the Society for Neuroscience.

As a clinician and surgeon, Dr. Rybak's special interests include general otolaryngology and sleep apnea. Known both nationally and internationally for his research in the field of otolaryngology, Dr. Rybak has published and presented numerous articles and chapters dealing with various aspects of ear, nose and throat diseases. He is certified by the American Board of Otolaryngology.

Research Interests/Areas of Expertise:

  • Growth of cochlear hair cells derived from Immortomouse (HEI-OC1, OC-k3 cells) in culture
  • Ototoxicity of cisplatin, carboplatin and loop diuretics and chemoprevention
  • Mechanisms controlling free radical production within the cochlea
  • Auditory development and ototoxicity during development
  • Scanning and transmission electron microscopy of the cochlea
  • Mechanisms of noise-induced hearing loss and pharmacological prevention
  • Cell death and cell replacement pathways in the cochlea


Medical School: 
Medical College of Wisconsin, Milwaukee, WI
University of Minnesota, Minneapolis, MN - Otolaryngology



Endogenous Modulation of Cochlear Injury. Leonard P. Rybak, MD, PhD,  Principal Investigator, National Institutes of Health, National Institute on Deafness and Other Communicative Disorders (R01 DC 02396-18A1, competing renewal, March 1, 2014-February 28, 2019,  total direct costs $1,062,500*.

Transplatin:  A Novel Agent to Mitigate Cisplatin Toxicity, Vickram Ramkumar, Principal Investigator, Leonard P. Rybak, co-investigator, National Cancer Institute, R01 CA 166907-01A1, July 1, 2013-June 30, 2018, total costs $1,500,000*.

Phase II Clinical Trials; D‐methionine to Reduce Noise‐Induced Hearing Loss. Department of Defense Kathleen Campbell PhD, PI, Co-Is Leonard Rybak, MD. PhD Joseph Milbrandt,PhD, Maj Jillyen Mathis AuD, Carrie Redlich, MD, Martin Slade MPH. ($2,568,584.99) March 1, 2011 through Feb 28, 2016*.